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March 22, 2012 -- Although having a job offers some protection against the flu, a new report from the CDC shows that workers in some industries appear more flu-prone than workers in other industries.

“[T]his information is needed for recognizing and responding to increased risks for infection among key occupational groups (e.g., health care workers, school teachers, retail and food service workers, and others with substantial exposure to the general public),” the authors write.

In the wake of the 2009 H1N1 pandemic, researchers with the CDC’s Emerging Infections Program (EIP) and the National Institute for Occupational Safety and Health (NIOSH) collected data from 3,365 adults whose flu had sent them to the hospital. Although hospitalizations for flu are not the norm, the report states, the authors’ aim was to provide “some clues about specific groups of workers that might be most commonly affected by severe influenza.”

Workers at Risk

Health care workers top the list. They account for more than 16% of all hospitalizations. Retail workers, at slightly above 12%, are not far behind. Accommodation and food service workers and educators each make up between 9% and 10% of the total number of those hospitalized.

Rather than simply look at the total number of hospitalized employees in each industry, the researchers also wanted to know which industries had the highest proportion of employees whose flu was severe enough to require a hospital stay.

They found that those in the transportation and warehousing industries -- airline workers, postal employees, and bus drivers, for example -- were more than 1.5 times more likely to be admitted to a hospital for flu than the average worker.

Nearly as likely were travel agents, janitors, secretaries, and other employees in the administrative and support services and waste management and remediation services. Health care workers followed close behind.

Educators, surprisingly, were no more likely to be hospitalized than the average worker.

Possible Underlying Causes

The authors say that it is hard to determine why some industries are more at risk than others, though they do offer some potential explanations.

“Overrepresentation of an industry sector in the EIP data set may be related to demographic and underlying health characteristics of the sector’s work force that put them at increased risk for acquiring influenza and for being hospitalized with influenza,” the authors write, “but it may also partially reflect occupational risk factors for influenza (e.g., exposure to ill members of the public).”

For example, more workers in the accommodation and food services smoked than in any other industry. They were also among those with the lowest incomes and the least likely to have a regular doctor. Educators, meanwhile, may be less likely to require a hospital stay because of their comparatively higher salaries and better access to health care.

But such factors can’t account for all the hospitalizations, the authors conclude.

“[M]ore research is needed to understand the reasons for the increased incidence of severe influenza among specific groups of workers,” they write. “Concurrently, any interventions that focus on these groups of workers should be evaluated for effectiveness and efficiency.”